Elastic fluid compressor of the jet type



'March 28, 1950 c. K. NEWCOMBE ELASTIC FLUID COMPRESSOR OF THE JET TYPE 2 Sheets-Sheet 1 Filed June 19, 1946 M f w e V n I CZake K M? WCO'YWZe March 28, 1950 c. K. NEWCOMBE 2,502,270

ELASTIC FLUID COMPRESSOR OF THE JET TYPE Filed June 19, 1946 2 Sheets-Sheet 2 Ira 671501 g6 CZZF /Ve wcomle Patented Mar. 28, 1950 ELASTIC FLUID COMPRESSOR OF THE JET TYPE Clare Kenzie Newcorribe, Fleet, England, assignor to Heat Pumps Limited, London, England,1.a-

British. company Application June '19, 1946, SerialiNo. 677,886 In Great Britain April 13,1945

1 'I'hisinvention is-ior improvements in or re .lating to elastic fluid compressors of the type (hereinafter referred to as jet compressors of the type described) in which the kinetic energy of a'high speed motive fluid jet is used to induce, accelerate and compress a secondary stream of fluid. A single pressure stage of jet compressors of the type described usually comprises a motive fluid or power nozzle, a mixing throat and a difiuser in which the compression of the two streamstakes place. An object of the'presentinv-ention is to provid unimproved jet compressor of the type described having the characteristicsof high efficiency, good flexibility; compactness of design and in certain cases. ability to operate at extremely high temperatures. i

"The invention provides a jet-compressor of the type in whichthe kinetic energy of a high speed motive fluid jet is used to induce, accelerate and compress a secondary stream of fluid comprising in combination a plurality of power nozzles for'the motive fluid and associated respectively with" the power nozzles a plurality of separated lnductioncon'duits adapted for entraining streams of the secondary fluid and constituting'separate chambers within which said streams of secondary fluid will be intermixed with jets of motive fluid from the assoicated power nozzles, said induction conduits being arranged as a ring-like :series andbeing S disposed as to impart to the mixture of primary and secondary fluid in each seriaratedconduit a rotational movement about the axis of the aforesaid series.

According to a feature of the invention the i induction conduits may be of helical form disposed about the periphery of a member formed as a body of rotation, e. g. cylindrical, conical, hyperboloidal or ellipsoidal.

In one construction the compressor comprises inner and outer shells of .frusto-conical form nested one within the other to provide between them an annular gap within which is disposed a seriesof helical guide vanes spaced apart to constitute between adjacent members of the u 6 Claims. (Cl. 230-495) guide vane. 2'1 (see Figure 3). and fitted with a; sleeve 28 having ports 25'; 30 discharging through rectan- Figure '1' isa perspective view of the compressor, a section being broken .awayfor the sake of illustration,

Figure 2 is a perspective view of a .portionzof the inner bore of thecompressor, and

Figure 3 is anexplodedview of one ofthe guide vanes and the controlling members associated therewith.

Like reference numerals indicate like parts in the three figures. In Figures 1 and 2 certain of the guide vanes shave, iortclearness-iof illustration, been omitted.

In this example the compressor comprisesan inner shell and an outer shell 2| both. of frusto-conical form, the shellv 20 being nested within the shell 2l'so asto provide between them an annular gap 22 decreasing in depth-from the narrow to the broadend of the conical structure. The intake to the compressor is at the narrow end'of the structure as a whole, and the discharge at the broad end. Theshells 20, are :surrounded by a cylindrical casing 23, the space between the outer shell 2|. and thecasing 23 .forming an intake manifold 25 for thenprimary or motive fluid.

Between'the tW0=shells 20, '21 there is provided aseries of helical conduits ('hereinafterreferred to as the mixing conduits) each of rectangular section. Each mixing conduit is formed between adjacent elements-of a set of guidevanes 24 extending lengthwise in the gap, 22, helically disposedover the outer surface of the inner shell 20 and :bounded top and bottom by'the shells-2|, The vanes 24:8113 secured in position. by screws, by welding, or; in. any other convenient manner. Alternatively, the vanes may be formed 'integrallyWith the inner or outer shell.

Motive :fluid nozzles are provided at the leading wedge-shaped endsof. the-guide vanes 24,- each nozzle beingformed by a nose-cap .261arranged :in frontof the leading end of a corresponding Eachznose-cap 25 is bored outat gular passages 31 to opposite sides respectively of the leadingend of the associated guide vane. The flow. of motive fluid from the manifold .25 to the sleeve ports 29, is controlled by pistons 32 axially movable within the sleeves. ton 32 is formed with a longitudinal fluted pas sage 33 and circumferential recesses 34 through which the motive fluid has access to the sleeve 7 ports. 'The pistons 32 are axially movable at will, to increase or decrease the compressor capacity (by increasing or decreasing the effective Each pis area of the port openings) by means of a multilobe cam 35 located co-axially within the inner shell 20 and rotatable by any convenient means.

In operation, the motive or primary fluid is supplied through the manifold 25 to the outer ends of the sleeves 28, thence down the fluted passages 33 and through the sleeve ports 29, 30 to the passages 3|. Secondary fluid is thereby induced to flow through the mixing conduits between the guide vanes 24 and by virtue of the helical form of the conduits, the mixture of primary and secondary fluid is given a spinning motion. The discharge from the compressor is taken through a duct 40 and exit 4!. Passage of the compressed fluid to the duct 40 may be controlled by a diffuser, similar to that employed in centrifugal compressor design, comprising a ring of airfoil type blades 42 (see Figure 2) mounted on the broad end of the inner shell 20 and arranged for boundary layer suction. Motive fluid may be supplied from the manifold 25 to ejector slots formed in the blades 62.

In this example the compressor parts are so designed that (a) the ratio of the height of the entrance throat of each mixing conduit divided by its width is greater than 2.5, and (b) the ratio of the width of each guide vane 24 at the entrance throat divided by the width of the associated nose-cap 26 (also measured at the throat) is between the limits 0.75 and 1.50. Importance is attached to the foregoing featuresof design.

Various modifications may be made in the construction above described without departing from the essentials of the invention. For example, instead of employing the co-operating sleeves 28 and pistons 32, the motive fluid nozzles may be formed between the internal edges of the feed passages 2'! in the nose-caps 26, and the sides of the leading wedge-shaped ends of the associated guide vanes, the nozzle throat areas being adjustable by effecting relative approaching or separating movement between the guide vanes and the nose-caps. Again, instead of helical conduits on a conical surface, the spinning effect on the mixture of primary or motive fluid and secondary fluid may be obtainedas has already been indicated--by suitably directed conduits formed on hyperboloidal, ellipsoidal or equivalent surfaces. The motive fluid nozzles and mixing conduits may be arranged for either radial or axial flow.

I claim:

1. A jet compressor with stationary fluid flow channels and of the type in which the kinetic energy of a high speed motive fluid jet is used to induce, accelerate and compress a secondary stream of fluid comprising in combination a plurality of power nozzles for the motive fluid and associated respectively with the power nozzles a plurality of separated induction conduits adapted for entraining by jet compressor action "streams of the secondary fluid and constituting separate stationary chambers within which said streams of secondary fluid will be inter-mixed with jets of motive fluid from the associated power nozzles, said induction conduits being arranged in a ring-like series and being so disposed as to impart to the mixture of motive and secondary fluid in each separated conduit a rotational movement about the axis of the aforesaid series, without recourse to rotating fluid flow channels.

2. A jet compressor according to claim 1 comprising two stationary annular shells separated by a gap within which helical blades in a ringlike series are fixed to define the separated induction conduits aforesaid.

3. A jet compressor with stationary fluid flow channels and of the type in which the kinetic energy of a high speed motive fluid jet is used to induce, accelerate and compress a'secondary stream of fluid, comprising in combination inner and outer stationary shells of frusto-conical form nested one within the other to provide between them an annular gap, a series of helical guide vanes fixed within said gap and spaced apart to constitute between adjacent members of the series a set of induction conduits for the secondary fluid and a set of power nozzles associated respectively with the entry ends of the induction conduits for directing jets of motive fluid into said conduits.

4. A jet compressor of the type in which the kinetic energy of a high speed motive fluid jet is used to induce, accelerate and compress a secondary stream of fluid, comprising in combination inner and outer shells of frusto-conical form nested one within the other to provide between them an annular gap, a series of helical guide vanes disposed within said gap and spaced apart to constitute between adjacent members of the series a set of induction conduits for the secondary fluid and associated with the leading end of each guide vane a nose-cap arranged to provide a nozzle for directing motive fluid into the corresponding induction conduit, the throat area of the nozzle being adjustable at will.

5. A jet compressor as claimed in claim 4 in which the compressor parts are so designed that (a) the ratio of the height of the entrance throat of each induction conduit divided by its width is greater than 2.5, and (b) the ratio of the width of each guide vane at the entrance throat divided by the width of the associated nose-caps, also measured at the throat, is between the limits 0.75 and 1.50.

6. A jet compressor according to claim 4 in which each induction conduit is of rectangular cross-section and in which the nozzles aforesaid are mounted to direct jets of motive fluid along opposite side walls of each induction chamber, said Walls being constituted by the aforesaid guide vanes.

CLARE KENZIE NEWCOMBE.

REFERENCES CITED The following references are of record in the Decker Sept. 16, 1944 

